The Short Answer Educational content only, not medical advice. No test described here diagnoses concussion on its own, and concussion diagnosis remains clinical. The advanced imaging methods covered in this series are research tools that detect group-level differences and are not validated to diagnose or exclude concussion in an individual person. Be cautious about clinics selling scans or brain maps as diagnostic. Discuss any assessment with a concussion-experienced clinician who can interpret it alongside your history and examination. QEEG applies statistical processing to a standard EEG recording, quantifying the power of electrical activity in each frequency band at each electrode and comparing those values against a normative database to produce color-coded brain maps. Group-level differences after concussion are documented, typically involving increased slow-wave activity and altered connectivity measures. The American Clinical Neurophysiology Society published a practice guideline specifically addressing the use of quantitative EEG for diagnosing mild traumatic brain injury (Tenney et al., 2021). Commercial brain mapping services sold directly to patients frequently present QEEG as far more diagnostic than the professional guidance supports. It quantifies EEG frequency band power and compares it against normative data. A professional practice guideline addresses its diagnostic use directly. Commercial brain mapping frequently overstates what a map establishes. How QEEG Works A standard EEG records electrical activity from electrodes on the scalp. QEEG takes that raw recording and applies spectral analysis, decomposing the signal into frequency bands: delta, theta, alpha, beta, and gamma. It then calculates the absolute and relative power in each band at each electrode, along with derived measures such as ratios between bands, coherence between electrode pairs, and phase relationships. These values are compared against a normative database matched for age, producing standardized scores displayed as topographic color maps. The visual output is striking, and that appearance drives much of its commercial appeal. What Changes After Concussion The most consistently reported group finding is increased slow-wave activity, particularly in theta, alongside reduced alpha power and altered coherence between regions. These changes are interpreted as reflecting disrupted network communication, which fits the diffuse axonal injury model of concussion. Findings vary considerably between studies in magnitude, direction, and location, and they change over time since injury. The pattern is broadly consistent enough to be real at a group level and variable enough to complicate individual interpretation, which is the recurring theme across advanced concussion assessment methods. The Diagnostic Question The gap between detecting a group difference and diagnosing an individual is the central issue. Professional guidance from the American Clinical Neurophysiology Society examined the evidence for QEEG in diagnosing mild traumatic brain injury and set out the methodological requirements such a claim needs (Tenney et al., 2021). Key problems include heterogeneous acquisition and analysis methods between centers, normative databases whose composition and quality vary, extensive multiple comparisons across electrodes and frequency bands inflating false positive findings, and a shortage of studies reporting sensitivity and specificity for individual classification. What Else Produces Abnormal Maps QEEG findings are not specific to concussion, which limits their diagnostic value considerably. Attention deficit disorder, depression, anxiety, sleep deprivation, medication including sedatives and stimulants, substance use, and normal individual variation all produce deviations from normative databases. Muscle tension artifact from the neck and jaw, common after a neck injury, contaminates the higher frequency bands. Drowsiness during recording shifts the spectrum toward slower frequencies, mimicking the classic post-concussion pattern. Distinguishing these requires expertise and clinical context that a map delivered as a standalone report does not provide. Where It Legitimately Fits Standard clinical EEG has an established role in concussion care for a different purpose: investigating suspected seizures, which occur after head injury and need specific treatment. That is a genuine indication and is read visually by a neurophysiologist rather than by database comparison. QEEG itself remains primarily a research method. For persistent post-concussion symptoms, clinical assessment identifying treatable vestibular, cervical, visual, sleep, and mood contributors changes management in a way a brain map generally does not (Silverberg et al., 2020). Cost matters here, since commercial mapping is often expensive and self-funded. Assessment identifies what is driving symptoms. Cervical and vestibular contributors are among the most commonly found and the most treatable. Start your 3-day free trial for joint-specific mobility programming addressing the neck side of those findings. Supporting Mobility Routine JME 14 Chin tucks reduce the upper cervical tension driving cervicogenic headache, one of the most common findings on post-concussion assessment. Ten repetitions with 5-second holds. JME 1 Cervical rotation restores segmental mobility, which is directly relevant where assessment identifies a cervical contribution to dizziness. Ten repetitions per direction. JME 15 Cervical lateral flexion addresses side-bending restriction sustaining neck tension and headache. Ten repetitions per side. JME 16 Cervical flexion and extension restore sagittal mobility restricted by suboccipital guarding after impact. Eight slow repetitions. JME 2 Cervical retraction reinforces a neutral head position, reducing the postural strain that worsens symptoms during screen-based testing. Ten repetitions per set. JME 150 Thoracic rotation restores mid-back motion, which reduces compensatory load on the cervical spine. Eight repetitions per direction. JME 227 Overhead reach opens the thoracic spine and rib cage, supporting the breathing mechanics behind nervous system regulation. Ten repetitions with controlled tempo. JME 155 Diaphragmatic breathing lowers sympathetic drive, which reduces the symptom load that degrades performance on any cognitive assessment. Ten slow breaths, several times daily. Start your 3-day free trial for joint-specific mobility programming addressing the cervical contributors assessment identifies. Common Mistakes Treating a QEEG map as diagnostic proof of concussion Ignoring that sleep deprivation and medication produce similar patterns Overlooking muscle artifact from a painful neck contaminating the recording Accepting a standalone report without clinical interpretation Paying substantial sums for mapping before basic clinical assessment Confusing QEEG with clinical EEG for suspected seizures Assuming a normal map excludes ongoing post-concussion problems Progression Start with clinical assessment identifying treatable vestibular, cervical, visual, sleep, and mood contributors, since these change management directly. Where seizures are suspected, request standard clinical EEG read by a neurophysiologist, which is a specific and appropriate indication. Treat QEEG as a research method rather than a diagnostic step, and if considering a commercial service, ask what the result would change about treatment before paying. Reassess persistent symptoms clinically rather than seeking further imaging or mapping. What does QEEG measure? The power of electrical activity in each frequency band, delta through gamma, at each scalp electrode, plus derived measures such as band ratios and coherence between electrode pairs. These values are compared against an age-matched normative database and displayed as topographic maps. Can QEEG diagnose a concussion? Professional guidance from the American Clinical Neurophysiology Society addressed this question directly and set out the methodological requirements such a claim needs. Group differences after concussion exist, and the gap between a group difference and individual diagnosis remains the central limitation. What else causes abnormal QEEG findings? Attention deficit disorder, depression, anxiety, sleep deprivation, sedative and stimulant medication, substance use, normal individual variation, drowsiness during recording, and muscle tension artifact from a painful neck all produce deviations resembling post-concussion patterns. Is EEG ever useful after a concussion? Yes, standard clinical EEG read visually by a neurophysiologist is appropriate where seizures are suspected after head injury, which is a genuine indication needing specific treatment. That differs from QEEG database comparison sold as brain mapping. Should someone pay for commercial brain mapping? Ask what the result would change about treatment before paying, since the answer is often nothing. Clinical assessment identifying treatable vestibular, cervical, visual, sleep, and mood contributors generally changes management where a map does not. How These Tools Fit Together Concussion diagnosis is clinical. It rests on the injury mechanism, the symptoms, and the examination, and international consensus guidance is explicit that no single test establishes or excludes the diagnosis (Patricios et al., 2023). Everything described in this series sits in a supporting role. Sideline and clinic tools such as SCAT6, VOMS, and King-Devick add structure and reproducibility to the clinical assessment. Computerized cognitive batteries quantify one specific domain. Advanced imaging methods detect group-level differences in research populations and are not validated for individual diagnosis (Maas et al., 2022). Confusing these roles is the most common error patients and clinicians make. What Assessment Is Actually For Confirming a clinical picture already suspected from history and examination Identifying which subtype is driving symptoms: vestibular, ocular, cervical, mood, sleep, or migraine Tracking change over time against the person's own earlier results Supporting return-to-play and return-to-work decisions with objective data Ruling out structural injury needing emergency treatment, which is what standard CT does Directing treatment toward the specific system involved Documenting recovery for insurance, legal, or occupational purposes Why Advanced Imaging Is Not Diagnostic Yet The barrier is not that these methods detect nothing. Diffusion imaging, functional MRI, magnetoencephalography, spectroscopy, and perfusion imaging all show reproducible group differences between concussed and control populations. The barrier is the gap between a group difference and an individual diagnosis. Concussion effects are small relative to normal human variation, findings differ in direction between studies and time points, most research lacks pre-injury baselines, acquisition and analysis methods vary between centers, and few studies report the sensitivity and specificity needed to classify one person (Lindsey et al., 2023, and Mayer et al., 2015). A test cannot be clinically diagnostic until it performs reliably on a single scan against a validated normative reference, and that threshold has not been met. Questions Worth Asking About Any Test Several questions separate useful assessment from expensive noise. Does the result change treatment, or only produce a label. Is there a baseline or normative comparison appropriate to your age, sex, and background. What are the sensitivity and specificity for individual diagnosis, and does the provider quote them. Would a concussion-experienced clinician interpret this alongside examination findings, or is it delivered as a standalone report. Is the test being sold directly to patients outside standard clinical pathways. Persistent symptoms usually reflect treatable vestibular, cervical, visual, sleep, or mood problems, and identifying those through clinical assessment changes management in a way most advanced imaging currently does not (Silverberg et al., 2020). References Patricios, J. S., Schneider, K. J., Dvorak, J., et al. (2023). Consensus statement on concussion in sport: the 6th International Conference on Concussion in Sport, Amsterdam, October 2022. British Journal of Sports Medicine, 57(11), 695-711. PubMed Echemendia, R. J., Brett, B. L., Broglio, S., et al. (2023). Sport Concussion Assessment Tool 6 (SCAT6). British Journal of Sports Medicine, 57(11), 622-631. PubMed Mucha, A., Collins, M. W., Elbin, R. J., et al. (2014). A brief Vestibular/Ocular Motor Screening (VOMS) assessment to evaluate concussions: preliminary findings. American Journal of Sports Medicine, 42(10), 2479-2486. PubMed Krause, D. A., Hollman, J. H., Breuer, L. T., et al. (2022). Validity indices of the King-Devick concussion test in hockey players. Clinical Journal of Sport Medicine, 32(3), e313-e315. PubMed Farnsworth, J. L., Dargo, L., Ragan, B. G., et al. (2017). Reliability of computerized neurocognitive tests for concussion assessment: a meta-analysis. Journal of Athletic Training, 52(9), 826-833. PubMed Wilmoth, K., Brett, B. L., Emmert, N. A., et al. (2023). Psychometric properties of computerized cognitive tools and standard neuropsychological tests used to assess sport concussion: a systematic review. Neuropsychology Review, 33(4), 675-692. PubMed Dretsch, M., Parish, R., Kelly, M., et al. (2015). Eight-day temporal stability of the Automated Neuropsychological Assessment Metric (ANAM) in a deployment environment. Applied Neuropsychology: Adult, 22(4), 304-310. PubMed Tenney, J. R., Gloss, D., Arya, R., et al. (2021). Practice guideline: use of quantitative EEG for the diagnosis of mild traumatic brain injury. Report of the Guideline Committee of the American Clinical Neurophysiology Society. Journal of Clinical Neurophysiology, 38(4), 287-292. PubMed Lindsey, H. M., Hodges, C. B., Greer, K. M., et al. (2023). Diffusion-weighted imaging in mild traumatic brain injury: a systematic review of the literature. Neuropsychology Review, 33(1), 42-121. PubMed Mayer, A. R., Bellgowan, P. S., & Hanlon, F. M. (2015). Functional magnetic resonance imaging of mild traumatic brain injury. Neuroscience and Biobehavioral Reviews, 49, 8-18. PubMed Huang, M., Lewine, J. D., & Lee, R. R. (2020). Magnetoencephalography for mild traumatic brain injury and posttraumatic stress disorder. Neuroimaging Clinics of North America, 30(2), 175-192. PubMed Hageman, G., Hof, J., Nihom, J., et al. (2022). Susceptibility-weighted MRI and microbleeds in mild traumatic brain injury: prediction of posttraumatic complaints? European Neurology, 85(3), 177-185. PubMed Eisele, A., Hill-Strathy, M., Michels, L., et al. (2020). Magnetic resonance spectroscopy following mild traumatic brain injury: a systematic review and meta-analysis on the potential to detect posttraumatic neurodegeneration. Neurodegenerative Diseases, 20(1), 2-11. PubMed Hamer, J., Churchill, N. W., Hutchison, M. G., et al. (2020). Sex differences in cerebral blood flow associated with a history of concussion. Journal of Neurotrauma, 37(10), 1197-1203. PubMed Alosco, M. L., Mariani, M. L., Adler, C. H., et al. (2021). Developing methods to detect and diagnose chronic traumatic encephalopathy during life: rationale, design, and methodology for the DIAGNOSE CTE Research Project. Alzheimer's Research and Therapy, 13(1), 136. PubMed Maas, A. I. R., Menon, D. K., Manley, G. T., et al. (2022). Traumatic brain injury: progress and challenges in prevention, clinical care, and research. Lancet Neurology, 21(11), 1004-1060. PubMed Silverberg, N. D., Iaccarino, M. A., Panenka, W. J., et al. (2020). Management of concussion and mild traumatic brain injury: a synthesis of practice guidelines. Archives of Physical Medicine and Rehabilitation, 101(2), 382-393. PubMed